Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759172Ab3DCDwn (ORCPT ); Tue, 2 Apr 2013 23:52:43 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:59266 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754750Ab3DCDwm (ORCPT ); Tue, 2 Apr 2013 23:52:42 -0400 MIME-Version: 1.0 In-Reply-To: <20130403030403.GA26913@redhat.com> References: <1364957903-10341-1-git-send-email-ming.lei@canonical.com> <20130403030403.GA26913@redhat.com> Date: Wed, 3 Apr 2013 11:52:39 +0800 Message-ID: Subject: Re: [PATCH] sysfs: check if one entry has been removed before freeing From: Ming Lei To: Dave Jones , Ming Lei , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Sasha Levin Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1288 Lines: 34 On Wed, Apr 3, 2013 at 11:04 AM, Dave Jones wrote: > On Wed, Apr 03, 2013 at 10:58:23AM +0800, Ming Lei wrote: > > > diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c > > index 1bf016b..328ef9b 100644 > > --- a/fs/sysfs/dir.c > > +++ b/fs/sysfs/dir.c > > @@ -268,6 +268,13 @@ void release_sysfs_dirent(struct sysfs_dirent * sd) > > */ > > parent_sd = sd->s_parent; > > > > + if (unlikely(!(sd->s_flags & SYSFS_FLAG_REMOVED))) { > > + printk(KERN_ERR "sysfs: free using entry: %s/%s\n", > > + parent_sd ? parent_sd->s_name : "", > > + sd->s_name); > > + BUG(); > > + } > > Please use WARN instead of BUG. For an in-ram filesystem like > sysfs, there's no real reason to lock-up the machine in this way > making it harder to debug. If WARN is used, the freed memory will be allocated to other kernel components, then sysfs may change the memory and cause destruction, so maybe it is better to use BUG to stop kernel. Thanks, -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/